Temple Run 2 is out on iPhone and iPad, with Android following swiftly

The original Temple Run game was (and still is) a phenomenon, with 170m downloads so far across iOS and Android.

Its sequel is thus one of the key game releases of 2013 on any platform: big news for tens of millions of people who couldn't give two hoots about the next Call of Duty. Its sequel – out on iOS now with Android following in a week's time – won't disappoint them.

If you're new to Temple Run, here's a primer: it's an "endless runner" game where your character has to run (and leap, turn and slide) for as long as possible without falling to their doom, smacking face-first into trees or bridges, or getting caught by the giant monkey that – for reasons unexplained – is chasing you. If you die, you go back to the start. Well, usually.

Temple Run 2 doesn't mess with the successful formula, with a simple set of touchscreen gestures used to control your runner. Swipe up to jump, swipe left and right to turn and swipe down to slide. These are the basic tools for avoiding the obstacles in your path, while collecting coins and power-ups along the way – the former by tilting your device right and left to run over the lines of coins.

So what's new? The graphics have been noticeably bumped up in quality, with the scenery around you noticeably richer in detail. Developer Imangi Studios used the Unity development platform for Temple Run 2, and has convincingly fleshed out the game's world.

There is some obvious "pop-up" on display – rocky crags and scenery that seems to pop up out of nowhere – but there's never any slowdown that impacts on the gameplay.

Also new: a mine-cart section where your character reaches the mouth of a mine then leaps into a cart, which you then steer safely through forks by tilting left and right, while ducking under stray beams. If Temple Run already had a dash of Indiana Jones in its DNA, it's even clearer here – and a welcome inclusion.

As before, there are several characters you can play. Four initially: Guy Dangerous, Scarlett Fox, Barry Bones and Karma Lee. Unlike the first game, the differences between them aren't purely cosmetic, thanks to the use of power-ups.

Shield protects you from obstacles, Boost whizzes you ahead at a faster pace, Coin Magnet attracts all the coins – all for a limited time.

Any character can grab these power-ups within the game by jumping into the air when they spot one hovering, but each character also has one power-up built in, triggered by double-tapping when they've collected enough coins to fill up a coin meter on the left-hand side of the screen.

The mine-cart section complements the core endless-running action well

Ah, coins. Temple Run 2 is a freemium game, like its predecessor. This time round there are two separate virtual currencies: coins and gems.

Coins are used to unlock Scarlett, Barry and Karma and upgrade their abilites – increasing the distance and duration of their power-ups, making the coin meter fill faster, increasing their score multiplier and so on. Each ability has five levels to upgrade to with increasingly powerful effects, and your upgrades are carried across whatever character you play as.

Gems are the other currency, and these are used for consumable items, like restarting from the point you died rather than the very beginning, or one-time boosts of power-ups.

You earn coins fast, and gems slow. Or you can buy both in the in-app store: coins run from 69p for 5,000 to £13.99 for 400,000, while gems go from 69p for five to £13.99 for 500. A one-time £2.99 payment for the Coin Doubler feature will help you earn coins faster, meanwhile.

Some freemium games can be over-aggressive with their in-app purchases, actively making the experience frustrating if you try to play too long without paying. Temple Run 2 isn't one of those: Imangi have judged the balance between free-play and paid features just about right.

As I said at the beginning of this review, Temple Run 2 is big news for tens of millions of gamers of all ages and abilities. And while it is a casual game in the sense that it's simple to pick up and play, it's also very easy to get sucked in to playing it in a hardcore way.

Lots of people who don't consider themselves gamers will love it. Kids will love it, but so will grandparents. Footballers will love it – Wayne Rooney has famously bragged about his Temple Run scores on Twitter.

But many veteran gamers – the people who DO give many hoots about the next Call of Duty – will also love Temple Run 2. It crosses demographic and gaming boundaries as easily as Guy Dangerous hops over dangling footbridges. An excellent sequel.